Electron discharge device



Nov. 23, 1937. MlLLER 2,100,308

ELECTRON DI SCHARGE DEVICE Filed NOV. 2, 1935 2 Sheets-Sheet l INVENTOR ATTORN EY 1937- c. F. MILLER ELECTRON DISCHARGE DEVICE Filed Nov, 2, 1935 2 Shgets-Sheet 2 INVENTOR BY ATTORNEY Mam Ev w? mv Patented Nov. 23, 1937 UNITED STATES ELECTRON DISCHARGE DEVICE Carl F. Miller, Emporium, Pa., grade Sylvania Corporation, corporation of Massachusetts assignor to By- Salem, Mass a Application November 2, 1935, Serial No. 47,922

11 Claim.

This invention relates to electron discharge devices and more particularly to means for supporting and shielding the electrodes of a-radio tube or similar device.

An object of the invention relates to a radio tube of the multi-unit type having improved means to space the electrodes and to isolate electrostatically certain electrodes of one unit from electrodes of another unit.

A feature of the invention relates to an improved form of electrostatic shield for radio tubes and the like.

Another feature relates to the novel organization, arrangement and relative location of parts which go to make up an improved radio tube, particularly one of the multi-unit type.

Other features and advantages not specifically enumerated-will be apparent after a consideraiton of the following detailed descriptions and the appended claims.

The invention is in the nature of an improvement on the type of electrode spacer disclosed in application Serial No. 749,344, filed .October 22, 1934, and while the present invention willbe disclosed in connection with its application to one particular type of radio tube it will be understood that this is done merely for explanatory purposes and not by way of limitation. Accordingly in the drawings,

Fig. 1 is an elevational view, partly in section, of a double pentode tube embodying the invention.

Fig. 1a is a detail view of the top-cap and spacer. V

Fig. 2 is a perspective view of the combined electrode spacer and electrostatic shield shown in Fig. 1.

. Fig. 3 is an edge view of one-half of the spacershield member of Fig. 2 looking in the direction of the arrows.

Fig. 4 is an enlarged view showing one preferred manner of fastening the parts of the spacershield member together.

Fig. 5 shows a tube embodying a modification of the spacer-shield member of Fig. 2.

Fig. 6 is an enlarged perspective view of the modified form of spacer-shield shown in Fig. 5.

Fig. 7 is an edge view of one-half of the spacershield of Fig. 6.

Fig. 8 is an enlarged detail view of a portion of the spacer-shield of Fig. 6.

Referring more particularly to Fig. 1, the numeral i represents in dotted outline,'any wellknown form of radio bulb or enclosing envelope which is sealed to the re-entrant stem 2, the latter terminating in the usual press 3. Sealed into the press 3 are the various lead-in and support wires 4 to l3 inclusive. The particular tube shown in the drawings is of the double pentode type, the two pentode units being situated vertically one above 5 the other. As is well-known the pentode unit comprises an electron emitting cathode, a control grid, a shield grid, a suppressor grid, and an anode. In the tube illustrated, the cathode i4 is of the indirectly heated type and comprises in 10 general a tubular metal sleeve extending centrally through both pentode units. The upper portion of this sleeve which acts as the cathode for the upper pentode unit is provided with an electron emissive coating, and likewise the lower portion is 15 provided with a similar coating to act as the cathode for the lower pentode unit. Any suitable form of heater filament may be insulatingly mounted within the sleeve I4 and the ends of this filament are connected to the lead-in wires, 20 8, 9.

Surrounding the lower cathode section, is a control grid consisting of afine wire helically wound around and fastened to the grid side-rods i5, it, the latter being connected to the lead-in 25 wire iii. A similar control grid wound around a pair of side-rods i1, i8 surrounds the upper cathode section. It will be noted that the control grids are electrically distinct from each other. On the other hand, the shield grid for the lower 80 pentode unit is electrically connected to the shield grid for the upper unit by reason of the fact that the side-rods i9 extend through both units, one of these side-rods being fastened at its lower end to the lead-in wire 1. Likewise the suppressor grid for the upper pentode unit is electrically connected to the suppressor grid for the lower pentode unit since the side-rods 20 extend through both units. The left-hand side-rod '20 is connected by a short metal strap 2i to the support rod 5. The tubular plate or anode 22 for the upper unit is fastened to the support rods 5 and i 2 while the tubular plate or anode 23 for the lower unit is fastened to the support rods 6, ii.

The anode or plate of the upper unit is electro- 45 statically shielded by a correspondingly shaped tubular metal screen 24 which is electrically connected by a wire (not shown) to the inner shield grid which is supported on the side-rod It. The top of the screen 24 is substantially entirely closed 50 off by a metal cap 25 which however is provided with a central slot (Fig. 1a) through which pass the various side-rods as shown, it being understood that there is seated in the metal cap 25 a disc 28 of insulation such as mica having perforaelectrodes, there is provided a special spacer mem ber which also serves to isolate electrostatically the upper and lower control grids. In accordance with the invention, this member is made in two symmetrical halves so that it may be assembled in place after the assembly of the various electrodes. As shown in detail in Fig.- 2, this com.- bined spacer-shield comprises a shallow metal cup 21 formed in two halves which may be pivotally united as indicated by the numeral 29 (Fig. 2). The bottom 29 of each half of the cup is provided with three perforations to receive the fastening members 30. Supported in spaced relation above the member 29 are two half-discs 3| of mica or other suitable insulating material. Similarly supported in spaced relation below the member 29 are two half-discs 32 of mica or the like. Each half disc is provided with perforations in alignment with the corresponding perforations in the bottom 29. For the purpose of fastening and maintaining. the insulator discs in their proper spaced relation to member 29 there are provlded insulator beads or washers 33 preferably of ceramic material and the members 30 pass through these washers, it being understood that the perforations in member 29 are slightly larger in diameter than the diameter of the members 39 as shown more clearly in Fig. 4. If desired, the members 30 may be made of hollow metal tubing so that when the cup 21 and the insulator discs are assembled, the ends of the members 30 may be flattened to prevent relative movement between the parts.

As shown more clearly in Fig. 2, the opposed edges of the two halves of each disc as well as the opposed edges of the two halves of the member 29 are provided with notches or slots through which pass the various side-rods. Thus when the two halves are in closed position the notches 34 define a circular opening, through which pass the-support rods 5 and I2 respectively, it being understood that the said rods are of slightly larger diameter than the openings defined by the notches so that the support rods can be clamped between the opposed edges of the half-discs. The notches 35 engage the grid side-rods 20; notches 36 engage side-rods l9. Notches 31 in the upper half-discs engage the control grid side-rods l1, l8 while the corresponding notches in the lower half-discs engage the corresponding side-rods l5, it of the lower control grid. Likewise the notches '38 engage the cathode l4. It will be noted that with elongated notches 39 so that the grid siderods I9, 20 do not contact with the said member 29. However, since the insulator half-discs are spaced from the member 29 it is possible to termi-. nate the ends of the control grid side-rods before they contact with said member 29. In the par ticular tube illustrated in the drawings the cathode I4 is connected by the jumper wire 40 to the member 5 which, in turn, is connected to the suppressor grid side rod 20. Since member 5 also supports the outer shield 24, the cathode I4 is therefore in electrical contact with outer shield 24 and the suppressor grid side rod 20. The control grids and the shield grids for the upper and lower units are however insulated from the said member 29. By this arrangement,

therefore, the separate control grids for both units are shielded from each other by the same shield member 29 which in conjunction with the insulator discs 3|, 32 also serves to maintain the various electrodes in their proper spaced relation, it being understood that when the two halves of the spacer-shield are closed they may be fastened in closed relation in any suitable manner.

Referring to Figs. 5 to 8, there is shown a modification of the invention wherein all the similar electrodes of the two pentode units are electrostatically shielded from one another. In this embodiment, the various electrodes and manner of support thereof from the press 3 are identical with those of Fig. 1 the only essential difference residing in the structure of the spacer-shield. In the embodiment of Fig. 5, the spacer-shield like that of Fig. 1 is made in two syirmietrical halves which are adapted to be 'closed against the various side-rods to preserve the spacing of the associated electrodes. As shown more clearly in Fig. 6, each half of the/spacer-shield comprises a bottom disc of a suitable insulating material such as mica, ceramic or the like, and a similar upper disc 4| of the same material. Clamped between the upper and lower insulator discs by means of the members 43 is the shielding member 42 in the form of a'shallow cup within which snugly fit the two half-discs 49. The opposed edges of the members 40, 4| and 42 are notched orslotted to receive the various electrode side-rods. Thus the notches 44 engage the plate support side-rods 4 and I3; the notches 45 engage the support rods 5 and i2; the notches 46 engage the suppressor grid side-rods 20; the notches 41 engage the shield grid side-rods I9; the notches 48 engage the control grid side-rods l1 and I8; and the central notches 49 engage the cathode sleeve l4. It will be noted that the opposed edges of the metal shield member 42 have notches that are similar to notches 44and 49 in the insulator disc but that elongated notches 50 are provided in the metal shield so that the rods 5, I2, I 9, 20 can pass therethrough without contacting with the metal shield. It will also be noted that in this embodiment, the screen 24 is welded or otherwise fastened to the downwardly turned rim of the shield member 40 consequently all the electrodes of the upper pentode unit are substantially entirely enclosed within an electrostatic shield thus electrostatically isolating the upper and lower pentode units from each other.

While certain specific embodiments of the invention have been disclosed herein, it will be understood that various changes andmodifications may be made therein without departing from the spirit and scope of the invention.

What I claim is:

1. A mount for a radio tube including a pair of longitudinally spaced electrodes, support wires for said electrodes each wire extending past both electrodes, and means to shield electrostatically said electrodes from each other, the last-mentioned means including a bi-part metal shield disposed between and fastened to corresponding bi-part insulation members the opposed-edges of saidshield and said members being notched to receive said support wires, said members clamping said support wires in the space between said electrodes.

2. A mount for a radio tube including a plu-' rality of pairs of electrodes in longitudinal spaced relation, support wires for said electrodes, and a unitary member for spacing said. electrodes and for electrostatically shielding the electrodes of one pair from the electrodes of the other pair, the last-mentioned means including a bi-part metal shield disposed between bi-part insulator discs and fastened thereto in the space between said electrodes, the opposed edges of the shield and the discs having aligned sets of notches to receive said support wires, said discs clamping said support wires, and means to fasten said shield and said discs together as a unit.

3. A mount for a radio tube including two separate-electron discharge units mounted one upon the other, each unit having an electron emitting cathode, an anode and a control grid, support wires extending through both units, and means to space the electrodes of each unit apart and to shield the control grid of one unit from the control grid of the other unit,'the last-mentioned means including a bi-part metal disc disposed between two bl-part insulator members and fastened thereto, the opposed edges of the disc and the opposed edges of the members having aligned sets of notches to receive said support wires, said members clamping said support wires in the space between said units.

4. A mount for a radio tube including a press, a plurality of pairs of metal support wires sealed into said press, a plurality of electrodes mounted at the upper end of said wires, a plurality of electrodes mounted at the lower ends of said wires, and unitary spacer-shield means disposed between the upper electrodes and the lower electrodes, said spacer-shield means consisting of a bi-part metal disc and an adjacent bi-part insulator member fastened thereto said disc and said member having aligned seats of notches in their edges to receive said support wires, said member clamping said support wires.

5. A mount according to claim 4 in which the insulator member of the spacer-shield is fastened to the metal disc in spaced relation thereto.

6. A mount for an electron discharge tube including a press, a plurality of pairs of metal support wires sealed into said press, a plurality of electrodes mounted at the upper end of said wires, a plurality of electrodes mounted at the lower ends of said wires, one of said electrodes being in the form of an outer tubular shield, and

means to complete the electrostatic shield at one end, the last-mentioned means including a bipart metal member having notches in the opprising a press, a plurality of sets of electrode side-rods one set of side-rods being sealed into said press, a combined shield-spacer in the form of a bi-part metal disc fastened between two bipart insulators the halves of the disc and insulators having notches in their opposed edges, said shield-spacer being positioned so that the siderods of one set pass through the disc and insulators while the side-rods of another set are situated in the notches in the insulator members but are terminated short of the disc.

9. A combined spacer-shield for radio tubes comprising a bi-part metal disc fastened between bi-part insulator members, the opposed edges of the bi-part disc and the opposed edges of the insulator members having aligned sets of notches,

some of the notches in the metal disc being of the same size as the corresponding notches in the insulator member and other notches in the metal'disc being larger than the corresponding notches in the insulator member.

10. A combined spacer-shield for radio tubes comprising a bi-part insulator member, another similar bi-part insulator member, a metal disc fastened between said members in spaced relation thereto, the opposed edges of the members and discs having aligned set of notches.

11. A combined spacer-shield for radio tubes comprising a cup-like metal member formed with two separable halves, an insulator member formed with two separable halves and seated within said cup-like member, and another insulator member formed with two separable halves, all said members being provided with aligned sets of notches in their opposed edges.

CARL F. MEIER. 

